Apparatus for making bisulfite of lime.



No. 646,268. Patented Mar. 27, I900. V. DREWSEN.

APPARATUS FOR MAKING BISULFITE OF LIM E.

(Application filed June 16, 1899.)

(No Model.) 2 Sheets-Sheet l.

No. 646,268. Patented Mar. 27, I900.

v. n'mawsauj APPARATUS FOR MAKING BISULFJTE 0F LIME.

(Application filed Tune 15, 1899.) (No Model.) 2 Sheets-Sheet 2.

VIGGO DRE\VSEN, OF NElV YORK, N. Y.

APPARATUS FOR MAKING B IS'ULFJTE OF LIME.

SPECIFICATION forming part of Letters Patent 0. 646,268, dated March 27,1900.

Application filed June 15,1899.

Serial No. 720,687. (No model.)

To aZZ w/tom it may concern.-

Be it known that I, VIGGO DREWSEN, a cit-izen of the United States,residing in'the city of New York, in the borough of Richmond and Stateof New York, have invented certain new.

and useful Improvements in Apparatus for Making Bisulfite of Lime, ofwhich the following is a specification.

In the production of bisultite of lime in sulfite-pulp millsconsiderable difiiculty has arisen heretofore in the summer season whichwas mainly due, as I have discovered, to the chemical heat generated inthe formation of to I have employed two tanks, one for uniting the milkof lime with the sulfurous-acid gas and forming thereby monosulfite oflime, and the second tank being a storage-tank for the monosulfite. itis preferable to carry out the process by means of three tanks: first, atank for cooling the milk of lime by neutralizing the chemical heatdeveloped when the lime is slaked second, a tank in which themonosulfite is produced, the cooling being continued in this.

tank, and a third tank in which the cooled monosulfite is changed intobisulfite. nection with the firsttankI'use several smaller tanks inwhich the burnt lime is first slaked, then mixed with an additionalquantity of water, and finally conducted into the larger tank. In thistank the milk of lime is cooled, so as to remove the chemical heatproduced by the slaking of the lime, and cooling means are provided inconnection with the second tank for removing the chemical heat producedduring the transformation of the lime into the monosulfite of lime; andthe invention consists of an apparatus for producing bisulfite of lime,which comprises a milk-of-lime tank, means for supplying milk of limethereto, a cooler connected with the milk-of-lime I have sincediscovered that In con-' I tank, a circulating-pump connected with thecooler and tank, a monosulfite-tank, a pipe connecting said pump withthe monosulfitetank, a cooler connected with the monosulfite-tank, acirculating-pump connected with the monosulfite cooler and tank, abisulfitetank,a pipe connecting the monosulfite-pump with thebisulfite-tank, and pipes for supplying successively sulfurous-acidgas-to the upper parts of'the bisultite, monosulfite, and milk-of-limetanks.

I In the accompanying drawings, Figure 1 represents a side elevation ofmy improved form of apparatus for producing bisulfite of lime, and Fig.2 is a plan View of Fig. 1.

Similar letters ofsreference indicate corresponding parts. In myimproved apparatus for producing bisulfite of lime three main tanks A,B, and 0 are employed, the tanks A and B being of the same size,preferably, but smaller than the tank 0. The tank A serves for receivingand cooling the milk of lime,'the tank B for bringing the charge of milkof lime into contact with sulfurous acid, so 'as to produce monosulfiteof lime, and the tank 0 for changing the monosultite into bisulfite oflime. Alongside of the tank A are arranged two auxiliary tanks, asmaller one A for bringing the burnt lime first in contact with water,so as to slake the lime. During the slaking the mass is agitated in asuitable manner and then transferredby means of the valved pipe a into asecond larger tank A in which it is mixed with a still larger quantityof water by continuous agitation, so that milk of lime of the properdegree of concentration is formed. Chemical heat is generated during theslaking of the quicklime in the tanks A and A so that the mass becomesheated. From the tank A the milk of lime in heated condition istransferred by means of the valved pipe a into the tank A. The heatedmilk of lime is cooled by arranging a cooler D, of any suitableconstruction, either cylindrical or coil-shaped, at one side of-the tankA, a circulating-pump P being arranged below the cooler, said pumpserving to draw the milk of lime from the tank A, forcing it through thecooler in upward direction, and returning it, after passing it throughthe cooler, into the upper part of the tank, as

Ioo

shown in the drawings. During this operation the valve d in the pipe a,leading from the circulating-pump P to the tank B, is closed. Thecontinuous circulation of the milk of lime, which is thus kept up in theprimary tank A and in the cooler D, removes the chemical heat andimparts such temperature to the milk of lime that the absorption ofsulfurous-acid gas can readily take place. When the milk of lime iscooled to the required low temperature, it is then pumped through thepipe a over into the tank B by means of the circulating-pump P, thecooler being cut out by the valve d. In the tank 13 it is brought intocontact with sulfurous-acid gas, so as to form monosulfite of lime. Thechemical heat developed by the absorption during the formation of themonosulfite is neutralized by arranging in the same mannor as with tankA a cooler E for the tank B and below the same a second pump P forkeeping up the continuous circulation of the monosulfite solution in thetank 13 and cooler E. lVhen the monosulfite has been formed and cooledto the required temperature, the valve 6 is opened and valve 6 closedand the monosulfite solution pumped by the pump P through the pipe 1)into the tank 0, in which it absorbs an additional quantity ofsulfurousacid gas, so as to form a solution or liquor of bisulfite oflime. This solution is kept in motion in the tank 0 by a thirdcirculating- 7 pump P which is arranged near the bottom of the tank 0and which keeps the solution in the tank in continuous circulationthrough the same and the pipe F, so as to bring the solutioncontinuously into contact with a quantity of fresh sulfurous-acid gasuntil bisulfite-of-lime liquor of the required strength is obtained. Nocooler is required for the tank 0, as no chemical heat is generatedduring the formation of the bisulfite of lime. By closing the valve fand opening the valve f the bisulfite may be pumped from the tank 0through the pipe 0 for use.

The sulfurous-acid gases are supplied from the sulfurburners by asupplypipe S, a blower S and a pipe S and then conducted from the upperpart of the closed tank 0 to the upper part of the tank B by a pipe 5,and from the upper part of the tank 13 by a pipe 8' to the tank A, andfrom the top of the latter by means of a pipe 5 and suction-fan S intothe atmosphere. The supply of sulfurous-acid gas is kept up in suchproportion that the entire quantity of gas is absorbed in the tanks Cand B. Should there be any unabsorbed gases, they are conducted into theupper part of the milk-of-lime tank A and absorbed in the same, so thata partial absorption of sulfurous-acid gas may take place in themilk-of-lime tank and none passes off to the atmosphere. Motion isimparted to the and fans referred to, as shown clearly in the drawings.Valved pipes G G G2 G G connected, respectively, with the tanks A, A

A, B, and C, are connected at their opposite ends with a supply-pipe H,which is connected with a suitable watersupply, (not shown,) so thatrequired quantity of water may be supplied to each tank at each stage ofthe process.

The process of making bisulfite of lime is carried out in the apparatusdescribed by first preparing the milk of lime in the auxiliary smallertanks A and A and then transferring thehot milk of lime into thefirsttank A and removing the chemical heat from the milk of lime in this tankby the cooler ar* ranged alongside of the same. The charge is thentransferred into the next tank 13, in which by the absorption ofsulfurous-acid gas monosulfite of lime is formed, the chemical heatbeing again removed by the cooler arranged alongside of this tank,through which the solution is continuously conducted. The charge ofmonosulfite is then transferred from the tank B to the larger tank 0, inwhich, by addition of water and the absorption of an additional quantityof sulfurous-acid gas, the bisulfite of lime is formed. As the charge ofmilk of lime is transferred from the front tank into the next adjacentone, the tank A is supplied with the charge which has been prepared inthe meantime in the preceding tank A and so on, so that the requiredquantity of bisulfite of lime proportioned to the requirements of thesulfite-pulp mill is produced. The proper low temperature of the liquorin the difierent tanks is maintained and the transfer is made at regularintervals of times, so that the process'can be carried on withoutdifficulty and with comparatively little watching of the solution in thetanks.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- The apparatus herein described for producingbisulfite of lime, consisting of a milkof-lime tank, means for supplyingmilk of lime thereto, a cooler connected with said milk-of-lime tank, acirculating-pump connected with the cooler and tank, a monosulfite-tank,a pipe connecting said pump with the monosulfite-tank, a coolerconnected with the monosulfite-tank, a circulating pump connected withthe monosulfite cooler and tank, a bisulfite-tank, a pipe connecting themonosulfite pump with the bisulfite tank, and pipes for supplyingsuccessively sulfurousacid gas to the upper parts of the bisulfite,monosulfite and milk-of-lime tauks,.substantially as set forth.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

VIGGO DREWSEN.

Witnesses:

PAUL GoEPEL, M. H. WURTZEL.

